The desorption of hydrogen from the monohydride species on Si(100) has been studied state specifically using (2+1) resonance‐enhanced multiphoton ionization. The monohydride phase was prepared by dosing the surface with either disilane (Si 2 H 6 ) or atomic hydrogen. Adsorption of disilane with subsequent desorption of H 2 leads to the growth of an epitaxial silicon film, based on evidence obtained with scanning electron microscopy and low energy electron diffraction. We report that the rovibrational‐state distribution for hydrogen desorbed from Si(100) is the same after both disilane and atomic‐H adsorption. Hydrogen desorbs with low average rotational energy but with a population in the v=1 state enhanced by roughly 20 times over a thermal distribution at the temperature of the surface. The agreement between internal‐state distributions for both adsorption schemes indicates that the desorption of hydrogen during epitaxial growth of Si after Si 2 H 6 adsorption proceeds in the same manner as that for a hydrogen‐prepared Si(100)‐(2×1):H surface.